Wire stripper for stripping outer conductors from coaxial lines



y 15, 1951 J E HELMINAK 2,553,316

WIRE STRI'PPE'IR FOR STRIPPING OUTER CONDUCTOR FROM COAXIAL LINES FiledJan. 27, 1949 2 Sheets-Sheet l INVENTOR. JOHN E. HELMINAK y 1951 J. E.HELMINAK 2,553,316

WIRE STRIPPER FOR STRIPPING OUTER CONDUCTOR FROM COAXIAL LINES FiledJan. 27, 1949 2 Sheets-Sheet 2 INVENTOR. JOHN E. HELMINAK Patented May15, 1951 WIRE STRIPPER FOR STRIPPING OUTER CONDUCTORS FROM COAXIAL LINESJohn E. Helminak, Washington, D. 0., assignor to the United States ofAmerica as represented by the Secretary of the Navy Application January27, 1949, Serial No. 73,178

1 Claim.

The present invention relate to tools, commonly known as wire strippers,for use in rcmoving an outer covering from a conductor. Morespecifically, it relates to strippers for facilitating the removal ofthe outer conductor from a coaxial pair.

Wire strippers are known wherein one element includes a pair ofgrippers, for holding a wire by its insulation, while the other elementincludes means for cutting through said insulation and pushing thelatter away, beyond the cut thus made.

However, the insulation that is handled successfully by strippers ofthis kind is, in general, much easier to out than the conductor enclosedtherein, and difficulty arises when it is attempted to strip, from asoft copper wire having enamel insulation thereon, a tough metalcovering, such as the tubular outer conductor of a coaxial pair. If thecutters are powerful enough to cut the tub ing, they will simultaneouslycrimp it about the inner wire and also leave a burr, oftenshort-circuiting the conductors of the pair, and also tending to nickand thus leave a weakened region of the central conductor at the cut.The present invention overcomes this defect by providing a modified typeof cutter, and additional members acting both as stops and as grippers.

An object of the invention is to provide a stripper which will make iteasy to remove a desired portion of the outer metallic conductor, toexpose a corresponding length of the insulated inner one, withoutinjuring it or causing a break or a short circuit between theconductors.

Other objects and many of the attendant advantages of this inventionwill .be appreciated readily as the same becomes understood by referenceto the following detailed description, whenconsidered in connection withthe accompanying drawings, wherein:

Fig. 1 is a front view of the stripper, partly broken away and insection;

Fig. 2 is a fragmentary side elevation;

Fig. 3 is a fragmentary detail, on an enlarged scale, showing a coaxialconductor gripped and nicked by the stripper;

Fig. 4 is a perspective view of one of the nickers, on a still largerscale;

Fig. 5 is a fragmentary detail, corresponding to Fig. 3, but showing theopposite side of the stripper, and showing a coaxial conductor grippedin the jaws. with its tubular outer conductor completely cut and readyfor removal;

Fig. 6 is a view ShOWil'lg the same structure as Fig. 5, but with thejaws separated, and the cut end of the outer conductor stripped off;

Fig. '7 is a fragmentary elevation, partly in section, on the plane I-!of Fig. 6;.

Fig. 8 is an end view of the stripper, with the jaw-end toward theobserver; and

Fig. 9 is a much enlarged elevation, partly in section, of a fragment ofcoaxial conductor that has been nicked and is ready to have its tubularconductor broken.

For convenience, the invention will be disclosed as embodied in amodified form of a known type of stripper, described in U. 8. Patents1,730,980 and 2,179,581. The detail structures of such conventionalstrippers are retained, as far as the manipulating means are concerned,only the operating head being changed.

Referring first to Fig. 1, the conventional tool comprises two handles,I, Z, resembling those of pliers and the like. Two levers 3 and 4 arepivoted together by a pivot screw 5, and are attached to the respectivehandles by pins I and 9, slidably engaged in the inclined slots 8 and IDin said levers.

Suitable relatively weak wire springs 2! and 22, housing in the handlesI and 2, conveniently made of sheet metal stamped into U-section, bearagainst the levers 3 and 4, partly housed therein, to keep the handlesseparated when in their idle positions, as illustrated.

A relatively strong spring 6 bears against the lower ends of levers3 and4, urging them apart, and thus holding together the upper ends of saidlevers, beyond the pivot screw 5.

According to the present invention, the upper end of levers 3 carries ajaw member I3, which is secured to said lever by a pair of screws I5,passing through lugs I9 on opposite sides of, and integral with, saidlever, one of the said screws being shown in Fig. 1. A coacting jawmember I4, which may be exactly like the jaw member I3, is similarlycarried by the handle I by means of screws I6.

It will be understood that each jaw member I3 and I4, has a gripper orjaw portion on one side thereof connected by integral through portionsthat serve to hold the jaws alined and, in the case of members I4 andIda, also bear slidably again the inner edges of levers 3 and 4respectively, to guide the handles I and 2 in operation.

On the ends shown in Fig. 1 these jaw members I3 and I4 clamp thenickers I1 and I8 between themselves and lugs I9 and 20, provided onlever 3 and handle I respectively. These nickers preferably are thinsteel blades, resembling the wafer-type blades in common use in safetyrazors. Their function is to produce nicks in opposite sides of thetubular conductor at the location where it is to be severed.

In the conventional type of stripper, when facing the front'of thelatter, cutting jaws are provided on one side of the tool, usually therighthand side, while the grippers are on the left side. In the presentdevice it is preferred to locate the nickers on the left; and to omitthe gripper entirely. This absence of grippers from the front or firstside of the tool is evident clearly in Fig. 1.

The nickers are preferably alike and thus interchangeable, and areshaped as shown in Fig. 4. While nicker I! alone is illustrated, it willbe understood that, if inverted, the illustration would equally wellpicture the nicker [8 in operating position. Each nicker comprises ablade 23 having a sharpened edge 24 and two slots 25 and 29. One cornerof the blade 23 is cut away, making said nicker of inverted L-shape.

As stated above, each nicker, l1 and i8, is held in place by thecorresponding jaw member, l3 and I4 respectively, by clamping it betweensaid member and the lugs I9 and 20. This may be accomplished by screws Iand IS, which pass through the slots and 26 of the nicker blades.

The other end of each jaw member has a jaw thereon, bent at right anglesto the direction of the length of levers 3 and 4, as is shown best inFig. 5. It will be understood that the jaw members It and is thatsupport the nickers have ping jaws 3| and 32 on their other ends.Preferably the work-gripping surfaces of said jaws are flat, and notserrated as in conventional strippers.

' This avoids injury to the relatively delicate tubular conductors to begripped by said jaws.

Thus one face of the tool carries no wire hold- 7 ing or manipulatingmeans except th nickers,

' whereas the other face has two pairs of laws or stops whichalternatively act as grippers. Each jaw member is supported by two lugs,with suitable screws passing through said lugs and threaded into the jawmember.

The operation of the tool is as follows:

The coaxial conductor that is to be stripped near its end is firstsuitably engaged by the tool, and the handles and 2 brought together, toforce the nickers l1 and l B into the tubular outer conductor 33 toproduce nicks 34 and 35 therein, as shown in Fig. 9. The nickers are soadjusted in the tool that even when the handles are squeezed together asfar as possible, so that stops 2! and 28 are in engagement, the saidnickers nevertheless are spaced apart sufficiently to prevent injury tothe inner conductor 36 of the coaxial pair, or even to force the tubularconductor 33 into contact with said inner conductor. This adjustmentvaries for different sizes of coaxial conductors, and is made possibleby the slots 25 and 26 of the nickers I! and I8.

Having nicked the outer conductor 33, the coaxial conductor is gentlybent back and forth,

manually, most easily but not necessarily while still engaged betweenthe nickers, to sever or cut said outer conductor 33 in the plane of thenicks. Some care is necessary to avoid injuring the inner conductor 36in the course of this manipulation, and consequently the bending shouldnot be through too great an angle.

The coaxial conductor, with its outer tubular conductor severed, is'nextplaced again in the tool, but this time on the rear or second side ofthe tool, in the position shown in Fig. 5. This View shows the coaxialconductor clamped in place, by the initial closing movement Qt the jawsthat occurs when the handles l and 2 first are brought together partly.Continued squeezing on the said handles will cause the other end of thetool to open, thus separating the two sets of gripping jaws, with theresult shown in Fig. 6, that is, with the'severed end of the outerconductor separated from the inner conductor. More specifically, theleft hand jaws grip and hold the complete coaxial conductor, while theright hand jaws grip only the severed end of the outer conductor 33, andpull it off the insulated inner conductor 35.

The nicker blades I! and 18 may be replaced from time to time, as theybecome dulled. This replacement is easy because of the slots 25 and 26,which make it unnecessary to remove the screws 15 and i3, which needmerely be loosened to permit removal of the worn out blades andinsertion and adjustment of the new ones in place thereof. 7

It will also be seen that while the invention has been disclosed withreference to one specific type of strippers, other types may also beused, for instance, that described in U. S. Patents 1,151,319 and1,196,322, by making suitable changes in details.

Obviously many other modifications and variations of the presentinvention are possibl in the light of the above teachings. It istherefore to be understood that within the scope of the appended claimthe invention may be practiced otherwise than as specifically described.

What is claimed is:

A wire stripper for use in removing the outer conductor from a coaxialcable, comprising two pivotally-connected members, one of said memberscarrying on its first sid a pair of nickers having opposed straightnicking edges, said nickers being slidable toward and from eachotherwhile maintaining said nicking edges parallel to each other, meanscomprising engageable stops mechanically connected with said nickers andslidably carried on the second side of said member to predetermine theminimum separation of said nickers, said stops being designedalternatively to act as grippers, the other member being unobstructed onthe corresponding first side to permit the cable to extend freelybetween the nickers, and a pair of stops acting as grippers slidablycarried on the second side of the other mem ber to coact with the firstpair of grippers, whereby the outer conductor of the cable may begripped on opposite sides of nicks previously made by the nickers, andpulled off the end of the central conductor.

JOHN E. HELMINAK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENT Number Name Date 552,490 Benecke Dec. 31, 18951,151,319 Wood Aug. 24, 1915 1,196,322 Wood Aug. 29, 1916 1,618,734Smitak Feb. 22, 1927 1,665,131 Ferrari Apr. 3, 1923 1,730,980 MontgomeryOct. 8, 1929 1,800,317 Ries et al. Apr. 14, 1931 1,924,837 Crause Aug.29, 1933 2,179,581 Voogd Nov. 14, 1939 2,217,077 Phillips Oct. 8, 1940

